Abstract: A comparative study on the mode of heating of the W-coated platform (heating transversely or longitudinally) in the GF-AAS determination of gallium was made. It was shown that a lower temperature of atomization, higher sensitivity and a wider range of linearity were found in the mode of longitudinal heating, but lower detection limit and better anti-interference ability were obtained in the mode of transverse heating. No significant differences were found in respect to the ashing temperature, amount of sample introduced, effect of different acid mediums and chemical modifiers, between the 2 modes.